Means for controlling electric meters.



3 SHEETS-$11331 1.

Inve nbor:

ilk/ 6y.

PATENTE D AUG. 23 1904,

y WiIHaZHF FaCQ by t W. H. PRATT. MEANS FOR CONTROLLING ELECTRIC METERS.

APPLICATION FILED JAN. 20, 1903.

N0 MODEL.

Wdness s: g? owa/ No. 768,844. PATENTED AUG. 23, 1904.

. W. H. PRATT. MEANS v1 0R vcomm-mum ELBOTRIG METERS.

APPLICATION FILED JAN. 20, 1903.

N0 MODEL.

8 SHEETS-SHEET 2.

No. 768,844. PATENTED AUG. 23, 1904.

W. H. PRATT.

MEANS FOR CONTROLLING ELECTRIC METERS.

APPLICATION FILED JAN. 20, 1903/ N0 MODEL. v a S EETS-SEEM 3.

lnvenU'on UNITED STATES Patented August 23, 1904.

PATENT OFFICE.

WILLIAM H. PRATT, or LYNN, MASSACHUSETTS, ASSIGNOR TO GENERAL ELECTRIC'COMPANY, A CORPORATION OF NEW YORK.

' tric meter into circuit when the number of MEANS FOR CONTROLLING ELECTRIC -METERS.

SPECIFICATION formingpart of Letters Patent No. 768,344, dated August 23, 1904.

v Application filed January 20 1903. Serial No. 139,830. (No model.)

To all whom itmcty concern:

Beit knownthat I, WILLIAM H. PRATT, a citizen of the United States, residing at Lynn, county of Essex, State of Massachusetts, have invented certain new and useful Improvements in Means for Controlling Electric Meters, of which the following is a specification. My invention relates to electric meters, and comprises means whereby. a meter or meters may be so controlled as to measure the energy of a circuit at such times only as the rate of flow of energy'is within certain predetermined limits. Thus, for example, my' invention is useful in cases where a certain flat rate is charged forcurrent when the amount of current flowing at any one time does not exceed a certain amount and a certain other rate when the flow of energy is in excess of the fixed-amount or limit. A meter 'or meters arranged in accordance with my invention may thus serve to measure the total amount of energy flowing only during such periodor periods as the flow of energy is in excess of a:

predetermined rate.

The meter-controlling mechanism which I employ is made up of a number of cooperating devices, the more prominent of which is an electrodynamometer for indicating the amount of energy flowing. This 'electrodynamomet'er through certain cooperating cir: cult-closmg dev1ces operates to cut an elecwatts being consumed is in excess of a certain amount and to cut the meter out of circult when the rate of consumption .of energy is less than the fixed amount.

My invention is intended more particularly for use in connection with polyphase electric circuits; but it will be evident that its various features of novelty are capable of useful applications in other relations than the particular one mentioned.

The features of novelty I have endeavored to point out with particularity in the appended claims, while the inventio'n'itself as to its details of construction and mode of operation is set forth more at length in the following description, which is to be taken in connection with the accompanying drawings, in which As before mentioned, the more prominent feature of the apparatus is the polyphase relay, this relay consisting of a species of dynamometer instrument having two fixed coils or current-carrying members arranged for connection, respectively, with two of the 5 three mains of the three-phase system, cooperating with which members are corresponding potential-coils, mounted within the influence of the current-coils and carried upon the same spindle. A contact-carrying arm is car- 7 riedby the spindle. The position of the con .tact depends upon the torque of the dynamometer as compared with the restraining torque of an adjustable spring. .By adjusting this Spring the contact may be arranged so that when the energy or, in other words, the watts of the multiphase circuit reaches or exceeds a certain amount the contact operates through adjunctive circuit-changing devices to throw into circuit a suitable polyphase meso ter, the meter being thrown out of circuit at other times. 7

In Fig. 1 the dynamometer instrument above mentioned is a somewhat rectangular arrangement mounted upon the four uprights 5 1, 2, 3, and 4, which in turn are supported from the horizontal brackets 5 and 6, bolted to the base-plate 7 of the instrument. One set of current-coils is indicated at 8 and 9, and

in order that the field produced by these coils 9 shall not only be as strong as possible, but also'shielded from external stray fields, I surround the coils by a mass of laminated magnetic material 10, having inwardly-projecting pole-pieces, as at 11, upon which the coils are mounted. The current-coils 12 and 13 of the other dynamometer element are similarlymounteduponinwardly-projectingpole-pieces formed integral with a body 14 of punchedout sheets of magnetic material similar to the mass or core 10. A view of the magnetic field structure for the current-coils is represented in cross-section in Fig. 4.

Between the inwardly projecting polepieees of the laminated cores 10 and 14 are mounted, respectively, two substantially cylindrical bodies of laminated iron, (indicated inFig. 4, at 15 and 16,) the arrangement being such that the movable coils 17 18, mounted on the spindle 19, swing in annular spaces, in each of which exists a strong magnetic field due to the current-coils of the instrument. The cylindrical blocks of magnetic material 15 and 16, around which swing the movable coils of the instrument, are supported in place by cross-bars 20, 21, 22, and 23, fixed, as indicated in Figs. 1 and 4, to the respective laminated cores 10 and 14, though of course any other suitable method of support may be employed if desired.

The spindle or shaft 19 of the movable member of the dynamometer carries an arm 24, the outer end of which is adapted to engage one or the other of two movable contacts indicated at 26 and 27 in Fig. 1, one of which is shown more in detail at 26 in Fig. 5. Current is conveyed to the movable contact 25 and also to the movable coils 17 and 18 by means of spiral springs, one of which is.

indicated at 28 in Fig. 4, to which the contact 25 and one end of each of the coils 17 and 18 are all connected, and two others at 29 and 30, to which the remaining ends of the two potential-coils 17 and 18 are connected.

The dynomometer instrument above described might be used as the direct means for cutting the electric meter controlled thereby into or out of circuit; but such an arrangement would be unsatisfactory,both because of the poor contact which would be afforded and the attendant sparking and other difficulties due to trembling engagement of the contacts and to the light pressure thereof, except in cases where the dynamometer be made of ex cessive size.

To overcome the diflieulties mentioned, I

arrange the apparatus so that the movable contact 25 is adapted to move over the two cooperating contacts 26 and 27 which are pivotally mounted at 30 and adapted to be moved periodically by magnetic means into the path traversed by the movable contact 25, carried by the dynamometer. If this latter contact is in one of its extreme positionsor at least away from its central position, it is engaged by one of the contacts 26 and 27, and if on the opposite side of its central position it is engaged by the other. Electrical connections are provided whereby when one of the contacts, as 26, is engaged a magnetic switch (indieated at 31) is thrown into a position such as to close the potential-circuits of an induction-meter, while when the other contact, 27

is engaged the magnetic switch 31 is moved into its opposite position, thereby opening the potential-circuits of the meter.

Before proceeding to describe in detail the various devices used in connection with the dynamometer it may for the sake of clearness be better to refer to Fig. 3, which is a conventional representation of the circuits of the system as a whole. In this ligure the two sets of current-coils of the dynamometer are indicated at 32 and 33. The corresponding potential-coils are indicated at 34 and 35, these coils being supposed to be mounted upon the vertical shaft 19. One set of current-coils, 32, is connected in series with one of the mains, 37, of the three-phase system represented conventionally by the set of mains 37, 38, and 39. The other set of current-coils 33 is connected in series with another of the three-phase mains, 39. Of the two potential-coils 34 and 35, it will be noted that the coil 34 is connected between the third main 38 and the main 37 and the other between the main 38 and the remaining main 39. The torque of the instrument as thus connected will, as is well understood in the art, represent the total energy llowing in the three-phase mains. Current flowing in the instrument tends to move the rotatable member carrying the contact 25 in one direction, and a spring-shown, for example, at 40 in Fig. 4--opposes the turning moment due to the current. By adjusting the tension of this spring 40 by means of the milled head or screw 41 the movable member of the dynamometer may be caused to occupy a central or neutral position at some particularly chosen load on the three-phase mains. When the load increases above this amount, the contact 25 moves to one side of the central position,while when the load is less than the lixed amount it is moved to the other side, thereby assuming in either case a position opposite one or the other of the contacts 26 and 27 before referred to.

By means of a periodically-energized electromagnet, represented at 42 in Fig. 5 and by the same numeral in Fig. 1, the contacts 26 and 27 are moved into the path of the contact 25, whereby the latter contact is brought into engagement with whichever of the contacts 26 and 27 it happens to register. The means for effecting this result is shown somewhat in detail in Fig. 5. 1n this ligure the magnet 42 will be seen to act upon an armature -13, pivoted about a shaft 44. The arms carrying the armature 43 project above the shaft 44, as indicated at 45, and carry contacts 26 and 27, which are firmly secured thereto but separated therefrom by suitable insulating material 46. The arms 45 are connected at the top by a yoke against which bears one end of a. spring 48,wound about the shaft 44,and acting at its other end upon a pivoted member 19. Thismember has arms connected at one side of the shaft by a yoke 47 and at the other side v 'reasaq. f

by a cross-barf 50, of insulating materiahsucjh as hard fiber, adapted when the armature 43 is drawn down by the magnet 42 to be pressed yieldingly against a fixed platform or pressure-receiving surface 51, also of insulating material. -When the magnet 42 is unenergized, the bar 50 is out of engagement with the pressure-receiving surface 51, leaving a space in whichthe end of the contact-carrying arm 24 is adapted to move freely back and forth. When the magnet 42 is energized, the end of this arm is immediately clamped against the pressure-receiving surface 51 by means of the bar 50, which action, is immediately succeeded by the movement of the resilient contacts 26 and 27 toward the platform or pressure-receiving surface'5l. The contact on the end of the arm 24 intercepts the movement of one or the other of said'contacts 26 and 27,

- dash-pot 63. Let it be supposed that the mag' and thereby completes a circuit through the switch-throwing device,(indicated in plan view in Fig. 1 and in perspective at the bottom of Fig. 1 at 31.)

The means whereby the magnet 42 is periodically energized may assume a variety of forms. One form which I have found suitable is shown in detail in Fig. 2. It consists of a suitable base 52, on which the workingparts are mounted. An electromagnet is represented at 53, and cooperting therewith is an armature 54, pivoted about its middle point at 55. This armature is provided with an open framework having an arm 56,.pivoted to asystem of levers. The lever 57, which is pivoted to the lever 56, carries at one end a cylindrical carbon contact 58, adapted to make engagement with a similar contact 59, secured to the base 52. A link connects the lever 57 with a pivoted lever 61, one end of which is adapted to communicate motion to the plunger 62 of a net 53, the circuit of which is completed by the engagement of the contacts 58 and 59, be connected in series with the circuit to be energized and across the terminals of a suitable source of current. The lever 56 will immediately be raised, the adjustment of the dashpot being such as to allow a quick upward -movement, the contacts 58 and 59 sliding over each other until the lower end 64 comes into engagement with the stop 65, carried by the base 52. This engagement causes the contact 58 to be tilted out of engagement with the fixed contact 59, whereupon the parts return ment of the lever 61 downward operates,

through the link 60, to draw down the upper end of the lever 57, thereby bringing the contact 58 against the contact 59, thus completing the'circuit, whereupon the sequence of operationsabove described is repeated;

By reference to Fig. 3 the-arrangement of circuits will perhaps be better understood. In this figure the magnet 53 of the device'shown in Fig. 2'is represented by the same numeral, and this magnet, it will be noted, is in series with the magnet 42 of the circuit-closing device shown in detail in Fig. 5 and in perspective in Fig. 1. This circuit-closing device, the operationof which has already been described, completes the circuits of a switchthrowing device shown in detail in Fig. 6 and in perspective at 31in Fig. 1. This device consists of two sets of magnets 69 70 and 71 72, provided with an armature fashioned in the form ofa cross, as represented conventionally at 73in Fig. 3 and more in detail by the same numeral in Fig. 6. Two of the diametrically-located magnets are energized when the contact 25 engages the cooperating contact 26 and the other pair when the contact 25 engages the cooperating contact 27. In one case let it be supposed that the armature 73 is moved so that the contact-carrying arm 74 in Fig. 6

the potential-coils into circuit with the mains 37, 38,'and 39, as indicated, whereuponthe meter commences to register. movement of the switch-closing device the contact 78 opens the circuit of thepreviouslyclosed pair of magnets 79,'thereby relieving the contact 25 of the dynamometer instrument of this duty and so preventing troublesome sparking. The remaining pair of magnets has its circuit closed by the contact 78 in readiness to be energized in case the contact 25 of the dynamometer instrument should move out of engagement with one of the contacts 26 27 and-into engagement with the other.

What I claim asnew, and desire to secure by Letters Patent of the United States, is:-

1. Thecombination of a multiphase altermating-current circuit, a meter therefor provided with current and potential circuits, and means for respectively opening or closing the said potential circuits when the load on said multiphase circuit falls below or rises above a predetermined amount.

2. The combination of a multiphase alternating-current circuit, an induction-meter therefor, means for setting said meter in operation when the load on said multiphase circuit rises above a certain amount, and means for throwing said meter out of operative re' lation to said multiphase circuit when the load falls below said amount.

' 3. The combination with the movable mem- By the same ber of an electrical indicating instrument, of a resilient arm carried thereby and having its outer end provided with a contact, a fixed pressure-receiving surface over which said contact is adapted to move in close proximity but out of engagement therewith, a series of cooperating contacts adapted to be periodically pressed. against said pressure-receiving surface thereby causing a firm engagement between one of said cooperating contacts and the first-mentioned contact, and a switchthrowing device controlled by the engagement of said contacts.

4. In a contact making and breaking device, the combination of a plurality of periodically and simultaneously actuated contacts, a pressure-receiving surface against which said contacts are adapted to be periodically pressed, and a pivotally-mounted contact arranged to move freely in the space between said pressure-receiving surface and the firstmentioned contacts when the latter are out of engagement with said surface.

5. The combination of apressure-receiving surface, a contact movable along said surface but out of engagement therewith, a plurality of contacts mounted so as to be movable into engagement with said pressure-receiving surface,thereby causing engagement between the first-mentioned contact and that one of the cooperating contacts with which it happens to register, and a circuit or circuits controlled by said engagement.

6. In a metering system for a multiphase circuit, the combination of adynamometer for measuring energy flowing in said circuit, a contact carried by the movable element of the cooperating contacts mounted so as to be capable of movement into the path of the contact on said contact-carrying arm, means for periodically advancing and withdrawing said cooperating contacts, and circuits controlled by the engagement of the contact on the contact-carrying arm with one or another of said cooperating contacts.

8. The combination of a pivotally-mounted contact, means for moving said contact backward and forward according to the variations in the amount of current flowing in an electric circuit, a series of contacts over which the pivoted contact is adapted to move, and means for periodically and simultaneously moving said series of contacts into the path of the pivotally-mounted contact.

In witness whereof I have hereunto set my hand this 17th day of January, 1903.

' WILLIAM H. PRATT. Witnesses:

DUGALD MoK. MoKlLLor,

J OHN A. MoMANUs. 

